This invention relates to a method for sealing an absorbent member, and more particularly to a method for sealing an absorbent member which is suitable for use as an absorbent core in a disposable absorbent article.
Absorbent webs which comprise masses of fibers, i.e., fibrous web, are well known in the art. Such webs can imbibe liquids, such as discharged body fluids, both by an absorption mechanism wherein fluid is taken up by the fiber material itself and by a wicking mechanism wherein fluid is acquired by, distributed through and stored in the capillary interstices between fibers. One means for improving the absorbency characteristics of such fibrous web structures is to incorporate therein superabsorbent material, such as polymeric gelling material (also referred to as hydrogel-forming material superabsorbent polymers, etc.) which imbibe fluid. The superabsorbent material serves to retain fluid such as discharge body liquids. An absorbent structure of this type wherein hydrogel-forming materials in particulate form are incorporated into fibrous webs is disclosed in Weisman and Goldman, U.S. Pat. No. 4,610,678, issued Sep. 9, 1986.
The improvement in absorbency provided by incorporation of absorbent gelling materials has permitted the realization of absorbent articles, such as disposable diapers, which employ relatively thin absorbent cores and which are, therefore, relatively thin products.
Notwithstanding the existence of absorbent cores as described above, there remains a need to provide absorbent cores which reduce and preferably eliminate the phenomena referred to as gel-on-skin. Gel-on-skin is the situation where absorbent gelling materials escape from the absorbent core and travel through the bodyside liner or topsheet of the absorbent article where they come into contact the wearer""s skin.
In prior art continuous lay down operations, fibers and superabsorbent materials are mixed together in a continuous web. The continuous web is then cut into individual absorbent members or cores. The individual absorbent members are then placed between a liquid pervious topsheet and a liquid impervious backsheet to form an absorbent article. Unfortunately, this configuration provided an unsatisfactory product as absorbent gelling material easily penetrated through the topsheet creating unacceptable amounts of gel-on-skin.
One solution to the above continuous lay down operation, was to place another web, such as a tissue or nonwoven web on top of the continuous web and then cut both the tissue and continuous web into individual members comprising the core and the tissue. The individual members were then placed in the product with the tissue positioned between the topsheet and the absorbent core substantially preventing absorbent gelling material from escaping from the uppermost surface of the absorbent core and thus reducing the amount of gel-on-skin.
Unfortunately, when for example, the tissue and the continuous web are cut into individual members, the ends of the absorbent core are left open, i.e., the ends of the absorbent core are not covered by the tissue, allowing absorbent gelling material to escape through the ends of the absorbent core.
It is an object of this invention to provide a method of sealing an absorbent core via a continuous lay down operation which circumvents the problems of gel-on-skin.
The invention is a method for sealing an absorbent member. To form the absorbent member, a web comprising a fibrous material and superabsorbent material is fed to a knife. The web has a first surface, a second surface, a first side edge and a second side edge. The knife cuts the web into individual absorbent members having a pair of opposing cut ends. The individual absorbent members have a first surface, a second surface, a first side edge, the second side edge, a first end edge and a second end edge, with the first and second end edges corresponding to the cut ends. A superabsorbent material movement obstruction agent is applied to the first and second end edges.
The superabsorbent material movement obstruction agent preferably extends from the first side edge to the second side edge, and from the first surface to the second surface of the individual absorbent members.
The individual absorbent members preferably form an absorbent core in a disposable absorbent article and are positioned between a liquid pervious topsheet and a liquid impervious backsheet.
As used herein, the term xe2x80x9csuperabsorbent material movement obstruction agentxe2x80x9d refers to an external agent, applied to a web comprising fibrous material and superabsorbent material, which obstructs the movement of the superabsorbent material through the cut end of the web.